1. Field of the Invention
This invention relates to an improved connector for connecting an electronic module or package, such as a multichip module, to a circuit board.
2. Description of the Prior Art
An important trend in the electronics industry has been the increasing utilization of integrated circuits as individual components due to their relatively inexpensive cost, miniature size, and electrical dependability. Today it is common for hundreds of complex integrated circuits to be treated as discrete components by the design engineer, with such integrated circuits being appropriately packaged and electrically connected to their associated printed circuit boards.
A multichip module can be defined as a packaging technology that places several such semiconductor chips, interconnected with a high-density substrate, into a single package. Multichip nodules often contain ASICs, microprocessors, and RCM circuits that require complex interconnect ribbon routings. Multichip modules and other such dense electronic assemblies typically include a large number of electrical terminals, and require electronic connectors that have a large number of densely packed electrical contacts. Often, the terminals are positioned on all four edges of a rectangular module, and a socket-type electrical connector having contacts located on four different sides is used for connecting the module to a circuit board.
Presently, several different techniques are being used to connect a high-density module to a circuit board such as a printed wiring board or mother board. One technique involves mounting the module to an elastomeric contact strip that has a pattern of conductive traces deposited thereon. Systems utilizing this technique, however, tend to be temperature-dependent, have relatively low reliability, require a cumbersome pressure fixture, are relatively large and require many parts.
A second connection technique involves attaching a multi-layer ceramic package to a circuit board with outside solder joints. Unfortunately, such packages are relatively expensive and very difficult to rework.
A third connection technique involves a multi-layer ceramic pin grid array. This tends to be expensive, though, and is not the more preferred surface mount technology ("SMT") design.
A fourth technique involves providing a socket for a leaded chip carrier. Such sockets, however, are not adjustable or readily designed to control contact and insertion forces, cannot regulate substrate stresses, and tend not to accommodate wide tolerances of chip packages or modules.
It is clear that there is a long and unfilled need in the prior art for an improved connector for a high-density leaded or leadless electronic module that allows for simple and effective regulation of insertion and withdrawal forces, is able to accept unpackaged electronic modules, is self-aligning and locking, and that accommodates wide tolerances.